A deadlock is a lock generally used for pedestrian doors, commomly entries and exits to bulidings of various types. A deadlock is a lock that is capable of being locked to prevent access and egress through a door.
Deadlocks are available in many different styles for a wide range of applications, for sliding and swinging doors, screen and security doors to assorted garage doors. Deadlocks characteristically fall into two (2) categories, deadbolts or deadlatches.
Daedbolts
A deadbolt is a form of deadlock where the locking bolt is a solid bolt, it typically has only 2 positions, locked or unlocked' however some deadbolts offer a double through bolt to penetrate the door frame further. A quality deadbolts bolt should go "dead" (be rigid when locked) to prevent entry by prying the locking bolt back to the unlocked position.
Deadlatches
Deadlatches are another form of deadlock where the locking bolt is in the form of a latch that is free to close and lock automatically simply by closing the door. As with quality deadbolts, the locking bolt on a quality deadlatch should go "dead" (be rigid when locked) to prevent entry by prying the locking bolt back to the unlocked position.